textproduct: Quad Cities

SHORT TERM /THROUGH TONIGHT/

Issued at 250 AM CDT Tue Jun 30 2026

The Extreme Heat Warning continues. Synoptic scale feature placement of the brunt of the ridge axis aligned from the lower MS RVR/TN Valley to the eastern OH RVR Valley and WV. This would make for a slow migration eastward of the northwest flank ring of fire storm track edging closer to us but brunt of the CWA may be spared until late in the week and the weekend. The far northwest and northern CWA may be brushed by convection sooner than that such as late tonight into early Wed morning. Back to the heat, with the NBM and high temps underachieving yesterday in the high humidity, will go just a degree or two warmer at most sites for highs today. This will make for widespread highs in the low to mid 90s, but the sfc DPTs are having no problem getting elevated and expect another day of mid to upper 70 values. Of course this will support heat index readings of a 100 to 108 degrees with pockets of higher values and the ongoing need for heat headlines.

As for the ongoing MCS acrs northeast NE into far northwest IA this morning, only the ECMWF brings a portion of this into the DVN CWA along and north of I-80 this morning. All other CAMs migrate this activity east-northeastward acrs southern MN into WI today and will cautiously play it that way, but of course will watch the upstream trends through the end of the shift whether to make changes on the fly.

Tonight...LLJ convergence on an elevated boundary with possible short wave rippling in southwesterly steering flow acrs the northwest half of IA will look to generate elevated showers and storms in a scattered west-east linear coverage pattern acrs the mid MO RVR Valley and acrs far northern IA/southwest WI late tonight. Most of this may remain just to the north of the local CWA but will have to have at least some low CHC POPs along the Hwy 20 corridor before they lift north by mid Wed morning.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 250 AM CDT Tue Jun 30 2026

Wednesday...As mentioned above, the latest ensembles and upper jet progs suggest the active southwesterlies edge closer to the western and northern side of the DVN CWA through mid week, before the flow will look to flatten and become more progressive acrs the north half of the CONUS by late week. Besides maybe some decaying debris spilling in acrs the west and north at times, feel the EML and lingering ridge centered off acrs the OH RVR Valley will maintain the mainly precip-free regime for one more day through Wed evening. Thus, with low to mid 90s still fcst with the ongoing high humidity, the Extreme Heat Warning will be allowed to ride acrs the entire area through Wed evening. After that, too much uncertainty about convection and associated debris/cool pools interrupting the heat acrs at least portions of the local area to extend the heat headlines further at this time. From mid Wed evening on into the early Thu morning hours, there appears the potential for a portion of an MCS to move into or form acrs the northwestern quarter to third of the DVN CWA and will have to have POPs to account for this. With all the available CAPE, and mature storm system moving into the area may be strong to severe with damaging winds until they maybe move more to the east and encounter the stouter EML and linger upper ridge lobe that would commence storm decay.

Thursday through Monday...The general pattern of flattened flow and broader zonal storm track acrs the upper mid CONUS may result in an unsettled period over the Holiday weekend with occasional rounds of showers and storms with passing even subtle short waves and probable MCV's. There will be a lot of dry hours mixed in as well. At the beginning of this longer range period, the latest ensembles suggest a stronger ridge-riding short wave upper trof to ignite a SD/NE MCS Thu evening with longer range thermal thickness steering guides taking at least a portion of this system into the CWA late Thu night into Friday morning...probably the northern half of the CWA and that's driving SPC's day-3 outlook risk areas. Details that far out still tough to call at this point, and it may be more of a far northern IA/MN/WI show into early Friday. Then it's day by day convective-wise for the rest of the period with one day's activity affecting the next day lay out with lingering outflow boundaries and synoptic fronts, something the models won't handle well close in, let alone this far out. The clouds, debris, and outflow could hinder ambient temp warm up into the 90s helping the cause to limit the need for more heat headlines, but the humidity and high sfc DPTs will unfortunately still be there for a very muggy holiday.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 630 AM CDT Tue Jun 30 2026

VFR conditions are expected throughout the TAF period. Some lingering low-level moisture under a temperature inversion has led to a stratus deck formation around 5 to 7 kft, extending from GGL northeast towards DBQ. Eventually, this deck should dissipate later this morning as the inversion mixes out. When it does, expect another period of gusty south-southeast winds, gusting to around 25 knots this afternoon.

As winds weaken overnight, we will have to keep an eye on the potential for at least marginal low-level wind shear tonight after midnight for BRL, MLI, and CID, given a persistent southwesterly flow aloft.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Extreme Heat Warning until 10 PM CDT Wednesday for IAZ040>042- 051>054-063>068-076>078-087>089-098-099. IL...Extreme Heat Warning until 10 PM CDT Wednesday for ILZ001-002- 007-009-015>018-024>026-034-035. MO...Extreme Heat Warning until 10 PM CDT Wednesday for MOZ009-010.